At around 1.20 p.m., a deflagration occurred during injection of a composite explosive (RDX type) under a press at an arms firm. The operation was remote-controlled from the control lane and viewed by means of a monitoring system through an in-house camera. The injection tooling was damaged. The explosive present in the press was recovered. A slight flash was visible on the recording video, barely perceptible and insufficient to trigger the automatic station flooding system which was therefore not actuated. The unit was decontaminated. Operations were stopped.

The person in charge of the injection operations was not the usual person. They had received their training a long time previously and had not received refresher training. They had no longer performed this operation since 2016. Moreover, the operational technical data sheet describing the operations of assembly/disassembly of injection tools was not sufficiently precise to make a clear distinction between the tool parts to be disassembled after each injection and the parts to be disassembled only at the end of the injection operation. At the end of the bomb loading cycle, the operator disassembled the injection tube coupled to the bomb to be loaded (planned disassembly) and the connecting tube supposed to remain coupled to the injection nozzle (disassembly not planned). Reassembly of this connecting tube on the injection nozzle in order to load a new bomb introduced a discontinuity in the composite explosive, leading to the presence of air between the explosive inside the reassembled connecting tube and the residual explosive in the injection pot.

After the incident, the operator took the following action:

• updating of the operational technical data sheet;
• conducting training in the machine operator’s job.